High IAT, clogged precats?

Hi all,

I'm lucky enough to have the California emissions package on my 2000 with the precats.

I recently got a ScanGauge and have been keeping an eye on my IAT readings. When driving on the highway, temps are 20 or so degrees above ambient. When I'm stopped or in traffic, IAT temps rise really quickly. No doubt this is aided by the precats being right under the intake. I have LeBaron hood vents, which help vent the heat being produced.

A few days ago I was nearly stopped for 15 minutes and the IAT rose to - and then leveled off at - 160 degrees. The ambient was 30 degrees or so. That IAT seems really high given that the ambient was low... kind of worried what it will be in the summer.

Any opinions if this reflects clogged precats?

My scan gauge shows similar temps under the hood on my 2000 with pre-cats that are only a year old. As long as you don't feel a significant loss of power or have any codes you should be fine.

Your numbers look fine. While moving ambient temp helps cool the engine bay to a degree. When stopped, as you say for 15 minutes, the engine bay becomes an oven.

Your temps are normal.
To reduce the intake temps, consider a cowl intake. It's a proven way to lower the temps by pulling in cooler air.
https://www.flickr.com/photos/lwade/sets/72157622703531169/

You can also mod the stock intake box for cold air intake through the headlight bucket. Here are some ideas.
http://jeep-xj.info/HowtoIntakeShield.htm
http://jeep-xj.info/HowtoRamInlet.htm

Awesome guys, thanks. Would be interesting to know how much heat the precats add. I wonder what IAT temps looks like for a Federal emissions XJ.